Remote Phone Book

[cluster]

Hello.
I'm trying to use the "Remote Phone Book" of my Yealink T27P, but im getting the Next error :
"Fail to download remote phonebook"

I'm using as my PBX a Denwa device. The format of the Contact List is as follows:

<contactData>
<group>
<contact sDisplayName="Ivan Drago" sOfficeNumber="107" sMobilNumber="" sOtherNumber="" sLine="0" sRing="Resource:Ring0.wav" group=""/>
<contact sDisplayName="Clint Eastwood" sOfficeNumber="113" sMobilNumber=""
<contact sDisplayName="Chuck Norris" sOfficeNumber="109" sMobilNumber="" sOtherNumber="" sLine="0" sRing="Resource:Ring0.wav" group=""/>
<contact sDisplayName="John Rambo" sOfficeNumber="108" sMobilNumber="" sOtherNumber="" sLine="0" sRing="Resource:Ring0.wav" group=""/>

<contact sDisplayName="Wonder Woman" sOfficeNumber="112" sMobilNumber="" sOtherNumber="" sLine="0" sRing="Resource:Ring0.wav" group=""/>
</group>
<blacklist/>
<groupinfo/>
</contactData>


For the Remote Phone Book i have the next parameters :
Index 1 :
Remote URL : http://192.168.4.20/xmlservices/contactData1.xml
Display Name : List

Can someone help me?
THank in advance.

REgards,
Ricardo